In a manufacturing process of semiconductor devices, a resist film is formed with a predetermined pattern on a film to be processed that has been formed on a substrate such as a semiconductor wafer (hereinafter referred to simply as “wafer”), and the film to be processed is subjected to processes such as an etching and an ion injection, by using the resist film as a mask. After the process, the resist film that is no more needed is removed from the wafer.
Recently, an SPM process is often used as a method of removing the resist film. The SPM process is performed by heating an SPM (Sulfuric Acid Hydrogen Peroxide Mixture) liquid, which has been obtained by mixing sulfuric acid solution and hydrogen peroxide solution, and supplying the heated SPM liquid to the resist film.
In the SPM process, the SPM liquid heated to a high temperature is generally discharged toward the wafer. Thus, the SPM liquid evaporates so that a fume is generated. The fume may diffuse over a wide range in a chamber of a resist removing apparatus, which contaminates or corrodes an inner wall of the chamber and components in the chamber, resulting in generation of a substance causing wafer contamination.
In order to prevent that the fume diffuses over a wide range in the chamber so that the inner wall of the chamber and the components in the chamber are contaminated or corroded, JP2007-35866A proposes a resist removing apparatus including: a substrate retaining unit configured to retain a wafer; a shielding wall surrounding a circumference of the wafer held by the substrate retaining unit and having an opening above the wafer; a cover member disposed above the shielding wall; and a nozzle inserted from a lateral side through a gap between the shielding wall and the cover member, the nozzle being configured to discharge the SPM liquid toward the wafer. According to the resist removing apparatus described in JP2007-35866A, diffusion of the fume over a wide range in the chamber is prevented by the shielding wall and the cover member.